Electricity Speeds: How Fast Does It Move?

In summary, the speed of electricity can vary depending on the form it takes. Electrons moving along a wire have a slow velocity of a few mm/s, while the electric field can move at a large fraction of the speed of light. In the case of lightning, there are multiple stages and factors that can affect the speed, with an estimated velocity of several hundred thousand mph. The visible streak of lightning can also vary in duration, with some types of lightning lasting longer than others. Overall, there is still much to be learned about lightning and its different forms.
  • #1
leroyjenkens
616
49
How fast does electricity move? It seems to move at different speeds when in lightning form. Like sometimes a bolt of lightning will be instant and then other times you can see it streaking kinda slowly across the sky.
 
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  • #2
Like a lot pf physics - it depends what you mean!

The speed of electrons moving a long a wire is very slow - a few mm/s, the speed of the electric field moving along a wire is a large fraction of the speed of light.

Lightning is a little more complicated, there are lots of stages in a lightning strike, the leader current, the return current, the ionization etc - but several 100,000 mph would be a reasonable estimate.
 
  • #3
Like a lot pf physics - it depends what you mean!
True. What I'm talking about is the visible streak that the lightning creates. Sometimes it's so fast, it looks like the entire bolt of lightning appears instantly. Then other times I can see the visible streak go across the sky. I was just wondering why there was a discrepancy.
The speed of electrons moving a long a wire is very slow - a few mm/s, the speed of the electric field moving along a wire is a large fraction of the speed of light.
It's weird, so the electrons actually don't move that fast, but they act kind of like a Newton's Cradle and thus the signal gets sent quickly?
 
  • #4
Check out this wikipedia article on lightning:
http://en.wikipedia.org/wiki/Lightning

Although it does not address your question directly, this article suggests a lot: namely, we still have a LOT to learn about lightning. The apparent different types of lightning, positive, negative,ball, cloud to ground,cloud to cloud, etc, suggests a lot we do not understand. It would seem possible that leaders in different types of atmosphere, say varying temperatures, humidities, varying degrees of particles in the air,etc might also affect lighting propagation As is evident in the article, many lightning activities are so quick they are largely imperceptible to our senses.

Also note the description of ball lightning which is believed to last longer than other "types"..so what you may see is not a difference is the speed of propagation but in the duration of the flash.
 
  • #5
leroyjenkens said:
so the electrons actually don't move that fast, but they act kind of like a Newton's Cradle and thus the signal gets sent quickly?
Yes - excellent analogy.
 
  • #6
Signals move in coaxial cables as a TEM (transverse electric magnetic) waves at about 0.66 to over 0.9 times the speed of light. The velocity of the signal depends primarily on the dielectric constant of the dielectric between the inner and outer copper conductors.
Stanford Linear Accelerator Center (SLAC) produces beams of electrons in vacuum at about 0.999999+ times the speed of light.
 
  • #7
Electron's move at mm/s in a wire? To a rough approximation of free electrons in an infinite, vanishing, periodic lattice do we not get that electrons go about 10% of c?
 
  • #8
Not to mention the observed propogation delays in digital circuits would not be consistent with such a slow speed
 
  • #9
maverick_starstrider said:
Electron's move at mm/s in a wire? To a rough approximation of free electrons in an infinite, vanishing, periodic lattice do we not get that electrons go about 10% of c?

No. Look up electron drift velocity.

As previously noted above, the speed of electrical signals you observe is not due to the motion of the electrons in a conductor but the propagation of the electric field in the space around the conductor. The velocity of this propagation is dependent upon the speed of light through the medium around the conductor; for free air this is about 98% c while for typical plastic insulations it varies between 50 and 75% c.
 
  • #10
maverick_starstrider said:
Not to mention the observed propogation delays in digital circuits would not be consistent with such a slow speed

Signal propagation speed is only very loosely related to electron propagation speed. The electrons move more like a train then individual cars. When a signal is applied it is felt by all electrons in the conductor. Signals propagate much faster then the individual electrons.
 

What is the speed of electricity?

The speed of electricity is typically measured in terms of how fast it travels through a conductive material, such as a wire. In most cases, it travels at a rate of approximately 299,792,458 meters per second, which is the same speed as light.

Does electricity always travel at the same speed?

No, the speed of electricity can vary depending on several factors, including the type of material it is traveling through, the temperature, and the amount of resistance it encounters. In some cases, it may travel slower or faster than the typical speed of 299,792,458 meters per second.

How does the speed of electricity compare to the speed of sound?

The speed of electricity is significantly faster than the speed of sound, which is approximately 343 meters per second. In fact, electricity can travel through a wire at a speed that is almost 1 billion times faster than the speed of sound.

Can electricity travel through all materials at the same speed?

No, the speed of electricity can vary depending on the type of material it is traveling through. For example, it can travel faster through materials that are good conductors, such as copper, and slower through materials that are poor conductors, such as rubber or glass.

How is the speed of electricity related to voltage and current?

The speed of electricity is not directly related to voltage or current. These are different properties of electricity that can affect its behavior, but they do not determine its speed. However, higher voltage and current can allow electricity to travel through a material more easily, potentially increasing its speed.

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